These thoughts may apply equally to any other online community as they do to the flash fiction one (or it's sub-community #fridayflash).
So I've had a little look around Google+ (or should that be Google Plus, I guess time will determine nomenclature, as it has with flash/ micro/ nano fiction... G+, maybe) and I've had time to gather a few thoughts together.
For those of you who don't know, one big feature of Google Plus is the circles. These are basically custom friends lists, but very heavily and slickly integrated. When you add someone to your Google+ you have to pick a circle to put them in (and yes you can put them in multiple circles, and removing them from a circle is as easy as click and a quick flick of the mouse to toss them away).
On a side note, they can't see what circle you've put them in, so you can happily add that annoying fellow at the desk next to yours to G+, so he stops pestering you, but put him in your 'ignore' circle and he will never know...
More importantly, this means that it's easy to just see your friends' posts, as distinct from your work colleagues' posts, as distinct from the 'people you met at a party once's posts. Obviously this functionality is available on facebook, but it isn't as easy, and facebook is drowning in bumpf and nonsense. Hopefully google+ won't head up spam creek as readily as facebook has.
The other side of circles is that when you yourself post, you can easily tag which circles can see it. Now the talk of circles has been of privacy and 'blah blah blah' elimination, which I think was the primary intent, but there is a very functional side effect of this too. (I knew I would get to the point sooner or later)
When you post you select which circles can see that content. So, what I currently do is use networked blogs on facebook to auto-post my fiction, once, to my friends. Then on twitter (@Xeroverse), I spam a little, it gets me more readers, and doesn't seem to lose me followers. That seems to be the etiquette on Twitter; it's a high speed, low impact environment. On facebook people miss important things their friends say, on Twitter people don't say important things. (OK, mass generalisation...)
Wait, I was getting to a point, wasn't I? So, with Plus I can have my flash fiction circle, and I can have my friends circle. I'd slap up a single public post of a new piece, so my friends can still read it, like some of them now do from facebook. And then I could throw up a couple of 'reminder' posts, set so only my flash fiction circle could see them. You say 'privacy', I say 'targeted'.
But because I'm in their flash fiction circle, I'm not spamming their friends circle/ stream either, they only need see me, and everyone else who wants their stories read, when they've already caught up with their real world friends.
Of course, one of the great things of the flash fiction community (at least, the parts I occupy) is the community part. So I would probably want to put my more general status updates open to all (I've never really been one to worry about keeping my thoughts private), so that will appear to the flash fiction folk too. However, when I post a video game trailer, something my friends will be into more, I can lock that to my friends circle.
I've seen people saying you should be able to censor people from your main stream, but I think people will get used to looking at individual circles (streams) in preference to everything at once, because that's the point.
Of course, some of this also depends on how Google integrates things like blogger too.
Just some thoughts. As more people move in the whole thing is going to develop rapidly, and we'll see how people choose to use it. It's both simple and complex enough that I think we'll see some totally unexpected new uses and behaviours emerge. It's kind of exciting... =)
John Xero <-- I am on Google Plus.
(As an afterthought... there's plenty of talk of it stealing people from facebook, and I think it might, but not much talk about twitter... could it? Might it? Will it be the one circle to rule them all?)